There are various planar display devices under development, such as a PDP display device, a liquid crystal display, an EL display device and an FED (Field Emission Device) display device. Displays (display panels) of those planar display devices are mainly composed of glass. For this reason, a planar display element composed of the glass is rigidly fixed on a chassis base (retention mechanism) composed of a metal plate such as aluminum or iron by using a two-sided tape for the purposes of securing strength and radiation. To fix the display panel composed of the glass on the chassis base, it normally requires the strength for making it hardly separable so as to be rigidly attached and fixed.
In recent years, it is becoming increasingly obligatory, from an environmental viewpoint, to separate materials and make cyclical use of reusable materials when disposing of these planar display devices. Under these circumstances, it has been considered that there is a necessity to have a technique of separating the display panel from the metal plate upon disposal in the case of a large-size planar display device of which one side exceeds 1 m. To be more specific, the chassis base includes aluminum and iron as its main components so that it can be easily recycled as-is. However, a PDP panel body includes lead and other chemical substances so that it needs to undergo a special process.
To separate the display panel from the chassis base, the two-sided tape must be cut or peeled in one way or another. As the two-sided tape have strong adhesion (attachment), however, it is difficult to separate the PDP panel body from the chassis base by a normal method.
As one of the techniques thereof, there is a proposed technique wherein a display panel body and a metallic chassis base for attaching the display panel body with an adhesive and thereby retaining it are provided, a heat generating member is placed in an adhesive material, and the adhesive is melted or degraded by heat of the heat generating member to reduce the attachment when separating the display panel body from the chassis base (Patent Document 1).
There is also a proposed technique wherein there are provided a display panel including multiple discharge cells and a chassis base for attaching a thermal conduction sheet to a back side of the display panel and thereby retaining the display panel, and the thermal conduction sheet is constituted by forming an adhesion layer on both faces of a thermally-conductive porous insulator sheet. And when attaching the display panel to the chassis base via the thermal conduction sheet, the thermal conduction sheet is attached to a front face of the chassis base first and then the back side of the display panel is lapped on the thermal conduction sheet of the chassis base so as to attach the display panel to the chassis base by means of the thermal conduction sheet. And when separating the display panel from the chassis base, cutting is performed by putting a cutting member through the porous insulator sheet portion of the attached sheet (refer to Patent Document 2 for instance).
There are also proposals of a method of cutting an adhesive layer between the display panel body and the chassis base by using a bandsaw and a wire (refer to Patent Documents 3 and 4 for instance), a method of heating the display panel body and the chassis base with electricity from a high-frequency power source and melting and peeling off the adhesive layer (refer to Patent Document 5 for instance), a method of attaching the display panel body to the chassis base by placing a pyroconductive member composed of a ductile peeling adhesive in a coasting manner, and reducing the attachment by pulling an end of the ductile peeling adhesive to separate them on peeling off (refer to Patent Document 6 for instance), and the like.    Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-123187    Patent Document 2: Japanese Patent Laid-Open Publication No. 2004-4705    Patent Document 3: Japanese Patent Laid-Open Publication No. 2004-29630    Patent Document 4: Japanese Patent Laid-Open Publication No. 2004-184677    Patent Document 5: Japanese Patent Laid-Open Publication No. 2004-111092    Patent Document 6: Japanese Patent Laid-Open Publication No. 2004-309547
According to the method described in Patent Document 1, the heat generating member is exposed at the end of the panel so that this portion needs to be processed. According to the method described in Patent Document 2, the cutting member needs to be put through the insulator sheet portion on cutting. According to the methods described in Patent Documents 3 to 5, it is necessary to provide equipment such as a saw device, a special tool or a high-frequency power source at a place for performing the disposal. Furthermore, according to the method described in Patent Document 6, a large amount of a particular kind of tape is used. Therefore, not only manufacturing cost becomes high but there is also a possibility that unevenness may occur in heat transfer between the PDP panel body and the chassis base to affect the screen, and besides, the ductile peeling adhesive may run out on peeling to disable the peeling.
The present invention solves the conventional technical problems, and an object thereof is to provide a planar display device which facilitates separation of the display panel body from the chassis base on disposal without preparing large-size equipment or a special tool. Another object of the present invention is to provide a planar display device of a low manufacturing cost, which does not use a particular kind of two-sided tape but uses an inexpensive wire.